Shares of Smith & Wesson (SWHC) and Sturm Ruger (RGR), the top two U.S. gun makers, surged early Wednesday in enormous volume. Firearms companies' stocks have risen in recent years on the prospect of tighter gun control measures, and the re-election of President Obama is seen as likely to ignite another sales surge. Gun sales were already at a brisk pace. Last Friday, the FBI reported adjusted firearms background checks -- a measure of future gun